The AP2331TD from Diodes Inc. is a single-channel current-limited load switch optimized for hot-swap applications. The AP2331TD provides fast overcurrent protection for improved USB port protection. This 0.2A single channel device is offered in SOT23 & SC59 packages for increased power density for multiple USB ports and other switch applications.
The USB specification does not allow an output device to source current back into the USB port. In a normal MOSFET switch, the current will flow in a reverse direction (from the output side to the input side) when the output side voltage is higher than the input side.
A reverse current limit feature is implemented in the AP2331TD to limit such back currents. Reverse current limit is always active in the AP2331TD.
Applications are expected to include notebook PCs, tablet PCs, motherboards, set-top-boxes, TVs, and telecom systems. Key features include:
- Current Limit Protection: The AP2331TD limits the max current to avoid damage of load and during overload conditions.
- Short Circuit Protection: The AP2331 senses the short circuit & immediately clamps output current to a certain safe level.
- Discharge Function: When input voltage falls below UVLO, the discharge function is active. The output capacitor is discharged through an internal NMOS with a discharge resistance of 1.8kΩ. Hence, the output voltage drops down. The internal discharge NMOS is turned off right away to avoid leakage current from output. The transient output discharge feature makes it suitable for HDMI or Display port applications.